Binary Lesson 6.1 Classful Subnetting 2

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24 Οκτ 2013 (πριν από 3 χρόνια και 7 μήνες)

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Binary Lesson 6.1

Classful

Subnetting

2

Slash Notation


Consider a class A address of 1.2.3.4


The network portion is the first octet


1


This situation can be written


1.2.3.4/8


The number after the / is the number of
bits in the network portion

Subnet Mask


Consider a class A address of 1.2.3.4 /8 in
binary


The
subnet mask

is 255.0.0.0


The network address is 1.0.0.0


In Binary:

IP:



00000001 00000010 00000011 00000100

Subnt Msk:

11111111 00000000 00000000 00000000

Net Addr:


00000001 00000000 00000000 00000000

AND


To find the network address, take a node's
IP address and do this:


If the Subnet mask bit is 1, keep the IP address bit


If the Subnet mask bit is 0, that bit changes to 0


This is called a bitwise AND operation


IP:



00000001 00000010 00000011 00000100

Subnt Msk:

11111111 00000000 00000000 00000000

Net Addr:


00000001 00000000 00000000 00000000

Class B


Class B address: 147.144.1.212 /16


The
subnet mask

is 255.255.0.0


The network address is 147.144.0.0


In Binary:

IP:



10010011 10010000 00000001 11010100

Subnt Msk:

11111111 11111111 00000000 00000000

Net Addr:


10010011 10010000 00000000 00000000

Class C


Class C address: 192.168.1.10 /24


The
subnet mask

is 255.255.255.0


The network address is 192.168.1.0


In Binary:

IP:



11000000 10101000 00000001 00001010

Subnt Msk:

11111111 11111111 11111111 00000000

Net Addr:


11000000 10101000 00000001 00000000

192.168.1.0 /25


You can split a class C in half with a /25


IP:



192.168.1.10 /25


Subnet Mask:

255.255.255.128


Network:


192.168.1.0


IP:



11000000 10101000 00000001 00001010

Subnt Msk:

11111111 11111111 11111111 10000000

Net Addr:


11000000 10101000 00000001 00000000

192.168.1.0 /25


There are only 128 addresses in a /25 block


Network:


192.168.1.0 /25


1
st

Usable:


192.168.1.1


Last Usable:

192.168.1.126


Broadcast:


192.168.1.127

Net Addr: 11000000 10101000 00000001 00000000

First Use: 11000000 10101000 00000001 00000001

Last Use:


11000000 10101000 00000001 01111110

Broadcast:

11000000 10101000 00000001 01111111

192.168.1.128 /25


There are only 128 addresses in a /25 block


Network:


192.168.1.128 /25


1
st

Usable:


192.168.1.129


Last Usable:

192.168.1.254


Broadcast:


192.168.1.255

Net Addr: 11000000 10101000 00000001 10000000

First Use: 11000000 10101000 00000001 10000001

Last Use:


11000000 10101000 00000001 11111110

Broadcast:

11000000 10101000 00000001 11111111

192.168.1.0 /26


There are only 64 addresses in a /26 block


Network:


192.168.1.0 /26


1
st

Usable:


192.168.1.1


Last Usable:

192.168.1.62


Broadcast:


192.168.1.63

Net Addr: 11000000 10101000 00000001 00000000

First Use: 11000000 10101000 00000001 00000001

Last Use:


11000000 10101000 00000001 00111110

Broadcast:

11000000 10101000 00000001 00111111

192.168.1.64 /26


There are only 64 addresses in a /26 block


Network:


192.168.1.64 /26


1
st

Usable:


192.168.1.65


Last Usable:

192.168.1.126


Broadcast:


192.168.1.127

Net Addr: 11000000 10101000 00000001 01000000

First Use: 11000000 10101000 00000001 01000001

Last Use:


11000000 10101000 00000001 01111110

Broadcast:

11000000 10101000 00000001 01111111

192.168.1.128 /26


There are only 64 addresses in a /26 block


Network:


192.168.1.128 /26


1
st

Usable:


192.168.1.129


Last Usable:

192.168.1.190


Broadcast:


192.168.1.191

Net Addr: 11000000 10101000 00000001 10000000

First Use: 11000000 10101000 00000001 10000001

Last Use:


11000000 10101000 00000001 10111110

Broadcast:

11000000 10101000 00000001 10111111

192.168.1.192 /26


There are only 64 addresses in a /26 block


Network:


192.168.1.192 /26


1
st

Usable:


192.168.1.193


Last Usable:

192.168.1.254


Broadcast:


192.168.1.255

Net Addr: 11000000 10101000 00000001 11000000

First Use: 11000000 10101000 00000001 11000001

Last Use:


11000000 10101000 00000001 11111110

Broadcast:

11000000 10101000 00000001 11111111

Classful Subnetting
iClicker Questions

How many subnets containing 9
hosts each can be made from
this network?

192.168.1.0/24

A.
4

B.
8

C.
16

D.
32

E.
Something else

How many subnets containing 90
hosts each can be made from
this network?

192.168.1.0/24

A.
4

B.
8

C.
16

D.
32

E.
Something else

How many subnets containing 9
hosts each can be made from
this network?

147.144.1.128/26

A.
4

B.
8

C.
16

D.
32

E.
Something else

How many subnets containing 2
hosts each can be made from
this network?

192.168.1.0/27

A.
4

B.
8

C.
16

D.
32

E.
Something else

How many subnets containing
900 hosts each can be made
from this network?

10.0.0.0/16

A.
8

B.
16

C.
32

D.
64

E.
Something else

What subnet contains this host?

192.168.1.129/30

A.
192.168.1.126 /30

B.
192.168.1.128 /30

C.
192.168.1.126 /29

D.
192.168.1.130 /30

E.
Something else

What is the smallest subnet
containing these two hosts?

192.168.1.1

192.168.1.10

A.
192.168.1.0 /24

B.
192.168.1.0 /26

C.
192.168.1.0 /28

D.
192.168.1.0 /30

E.
Something else

What is the smallest subnet
containing these two hosts?

10.1.1.2

11.1.1.1

A.
10.0.0.0 /8

B.
10.0.0.0 /7

C.
10.0.0.0 /6

D.
8.0.0.0 /6

E.
Something else

What is the smallest subnet
containing these two hosts?

147.144.128.129

147.144.128.193

A.
147.144.128.0 /24

B.
147.144.128.0 /25

C.
147.144.128.128 /25

D.
147.144.128.128 /26

E.
Something else

What is the smallest subnet
containing these two hosts?

192.168.1.62

192.168.1.65

A.
192.168.1.0 /24

B.
192.168.1.32 /25

C.
192.168.1.0 /25

D.
192.168.1.32 /26

E.
Something else